diff --git a/vendor/README.md b/vendor/README.md
index cbb1b43275459..bca3d5e10f3da 100644
--- a/vendor/README.md
+++ b/vendor/README.md
@@ -7,7 +7,7 @@ Therefore we put all common dependencies into this directory, `vendor`. This mea
 The process for updating a vendored dependency is:
 
 1. `npm install {DEP NAME HERE}`
-2. `cp -r node_modules/DEP vendor/DEP`
+2. `cp -r node_modules/DEP vendor`
 3. Update `eslintrc.js` to forbid importing DEP directly (see the `Mitt` rule already defined in there).
 4. Use the new DEP, and run `npm run tsc` to check everything compiles successfully.
 5. If the dep ships as compiled JS, you may need to disable TypeScript checking the file. Add an entry to the `excludes` property of the TSConfig files in `vendor`. (again, see the entry that's already there for Mitt as an example). Don't forget to update both the ESM and CJS config files.
diff --git a/vendor/mitt/README.md b/vendor/mitt/README.md
index b6a80225dfe32..08a21bf7adb24 100644
--- a/vendor/mitt/README.md
+++ b/vendor/mitt/README.md
@@ -69,6 +69,9 @@ emitter.on('*', (type, e) => console.log(type, e) )
 // fire an event
 emitter.emit('foo', { a: 'b' })
 
+// clearing all events
+emitter.all.clear()
+
 // working with handler references:
 function onFoo() {}
 emitter.on('foo', onFoo)   // listen
@@ -99,6 +102,7 @@ const emitter: mitt.Emitter = mitt();
 #### Table of Contents
 
 -   [mitt](#mitt)
+-   [all](#all)
 -   [on](#on)
     -   [Parameters](#parameters)
 -   [off](#off)
@@ -112,6 +116,10 @@ Mitt: Tiny (~200b) functional event emitter / pubsub.
 
 Returns **Mitt** 
 
+### all
+
+A Map of event names to registered handler functions.
+
 ### on
 
 Register an event handler for the given type.
diff --git a/vendor/mitt/dist/mitt.es.js b/vendor/mitt/dist/mitt.es.js
index 74aaf3a2413c1..889e27282f65c 100644
--- a/vendor/mitt/dist/mitt.es.js
+++ b/vendor/mitt/dist/mitt.es.js
@@ -1,2 +1,2 @@
-export default function(n){return n=n||new Map,{on:function(t,e){var i=n.get(t);i&&i.push(e)||n.set(t,[e])},off:function(t,e){var i=n.get(t);i&&i.splice(i.indexOf(e)>>>0,1)},emit:function(t,e){(n.get(t)||[]).slice().map(function(n){n(e)}),(n.get("*")||[]).slice().map(function(n){n(t,e)})}}}
+export default function(n){return{all:n=n||new Map,on:function(t,e){var i=n.get(t);i&&i.push(e)||n.set(t,[e])},off:function(t,e){var i=n.get(t);i&&i.splice(i.indexOf(e)>>>0,1)},emit:function(t,e){(n.get(t)||[]).slice().map(function(n){n(e)}),(n.get("*")||[]).slice().map(function(n){n(t,e)})}}}
 //# sourceMappingURL=mitt.es.js.map
diff --git a/vendor/mitt/dist/mitt.es.js.map b/vendor/mitt/dist/mitt.es.js.map
index 0f1670de46272..6576278e2da07 100644
--- a/vendor/mitt/dist/mitt.es.js.map
+++ b/vendor/mitt/dist/mitt.es.js.map
@@ -1 +1 @@
-{"version":3,"file":"mitt.es.js","sources":["../src/index.ts"],"sourcesContent":["export type EventType = string | symbol;\n\n// An event handler can take an optional event argument\n// and should not return a value\nexport type Handler = (event?: any) => void;\nexport type WildcardHandler= (type: EventType, event?: any) => void\n\n// An array of all currently registered event handlers for a type\nexport type EventHandlerList = Array<Handler>;\nexport type WildCardEventHandlerList = Array<WildcardHandler>;\n\n// A map of event types and their corresponding event handlers.\nexport type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;\n\nexport interface Emitter {\n\ton(type: EventType, handler: Handler): void;\n\ton(type: '*', handler: WildcardHandler): void;\n\n\toff(type: EventType, handler: Handler): void;\n\toff(type: '*', handler: WildcardHandler): void;\n\n\temit<T = any>(type: EventType, event?: T): void;\n\temit(type: '*', event?: any): void;\n}\n\n/** Mitt: Tiny (~200b) functional event emitter / pubsub.\n *  @name mitt\n *  @returns {Mitt}\n */\nexport default function mitt(all?: EventHandlerMap): Emitter {\n\tall = all || new Map();\n\n\treturn {\n\n\t\t/**\n\t\t * Register an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to listen for, or `\"*\"` for all events\n\t\t * @param {Function} handler Function to call in response to given event\n\t\t * @memberOf mitt\n\t\t */\n\t\ton(type: EventType, handler: Handler) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tconst added = handlers && handlers.push(handler);\n\t\t\tif (!added) {\n\t\t\t\tall.set(type, [handler]);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Remove an event handler for the given type.\n\t\t *\n\t\t * @param {string|symbol} type Type of event to unregister `handler` from, or `\"*\"`\n\t\t * @param {Function} handler Handler function to remove\n\t\t * @memberOf mitt\n\t\t */\n\t\toff(type: EventType, handler: Handler) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tif (handlers) {\n\t\t\t\thandlers.splice(handlers.indexOf(handler) >>> 0, 1);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Invoke all handlers for the given type.\n\t\t * If present, `\"*\"` handlers are invoked after type-matched handlers.\n\t\t *\n\t\t * Note: Manually firing \"*\" handlers is not supported.\n\t\t *\n\t\t * @param {string|symbol} type The event type to invoke\n\t\t * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler\n\t\t * @memberOf mitt\n\t\t */\n\t\temit(type: EventType, evt: any) {\n\t\t\t((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });\n\t\t\t((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });\n\t\t}\n\t};\n}\n"],"names":["all","Map","on","type","handler","handlers","get","push","set","off","splice","indexOf","emit","evt","slice","map"],"mappings":"wBA6B6BA,GAG5B,OAFAA,EAAMA,GAAO,IAAIC,IAEV,CAQNC,YAAGC,EAAiBC,GACnB,IAAMC,EAAWL,EAAIM,IAAIH,GACXE,GAAYA,EAASE,KAAKH,IAEvCJ,EAAIQ,IAAIL,EAAM,CAACC,KAWjBK,aAAIN,EAAiBC,GACpB,IAAMC,EAAWL,EAAIM,IAAIH,GACrBE,GACHA,EAASK,OAAOL,EAASM,QAAQP,KAAa,EAAG,IAcnDQ,cAAKT,EAAiBU,IACnBb,EAAIM,IAAIH,IAAS,IAAyBW,QAAQC,IAAI,SAACX,GAAcA,EAAQS,MAC7Eb,EAAIM,IAAI,MAAQ,IAAiCQ,QAAQC,IAAI,SAACX,GAAcA,EAAQD,EAAMU"}
\ No newline at end of file
+{"version":3,"file":"mitt.es.js","sources":["../src/index.ts"],"sourcesContent":["export type EventType = string | symbol;\n\n// An event handler can take an optional event argument\n// and should not return a value\nexport type Handler<T = any> = (event?: T) => void;\nexport type WildcardHandler = (type: EventType, event?: any) => void;\n\n// An array of all currently registered event handlers for a type\nexport type EventHandlerList = Array<Handler>;\nexport type WildCardEventHandlerList = Array<WildcardHandler>;\n\n// A map of event types and their corresponding event handlers.\nexport type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;\n\nexport interface Emitter {\n\tall: EventHandlerMap;\n\n\ton<T = any>(type: EventType, handler: Handler<T>): void;\n\ton(type: '*', handler: WildcardHandler): void;\n\n\toff<T = any>(type: EventType, handler: Handler<T>): void;\n\toff(type: '*', handler: WildcardHandler): void;\n\n\temit<T = any>(type: EventType, event?: T): void;\n\temit(type: '*', event?: any): void;\n}\n\n/**\n * Mitt: Tiny (~200b) functional event emitter / pubsub.\n * @name mitt\n * @returns {Mitt}\n */\nexport default function mitt(all?: EventHandlerMap): Emitter {\n\tall = all || new Map();\n\n\treturn {\n\n\t\t/**\n\t\t * A Map of event names to registered handler functions.\n\t\t */\n\t\tall,\n\n\t\t/**\n\t\t * Register an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to listen for, or `\"*\"` for all events\n\t\t * @param {Function} handler Function to call in response to given event\n\t\t * @memberOf mitt\n\t\t */\n\t\ton<T = any>(type: EventType, handler: Handler<T>) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tconst added = handlers && handlers.push(handler);\n\t\t\tif (!added) {\n\t\t\t\tall.set(type, [handler]);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Remove an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to unregister `handler` from, or `\"*\"`\n\t\t * @param {Function} handler Handler function to remove\n\t\t * @memberOf mitt\n\t\t */\n\t\toff<T = any>(type: EventType, handler: Handler<T>) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tif (handlers) {\n\t\t\t\thandlers.splice(handlers.indexOf(handler) >>> 0, 1);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Invoke all handlers for the given type.\n\t\t * If present, `\"*\"` handlers are invoked after type-matched handlers.\n\t\t *\n\t\t * Note: Manually firing \"*\" handlers is not supported.\n\t\t *\n\t\t * @param {string|symbol} type The event type to invoke\n\t\t * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler\n\t\t * @memberOf mitt\n\t\t */\n\t\temit<T = any>(type: EventType, evt: T) {\n\t\t\t((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });\n\t\t\t((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });\n\t\t}\n\t};\n}\n"],"names":["all","Map","on","type","handler","handlers","get","push","set","off","splice","indexOf","emit","evt","slice","map"],"mappings":"wBAgC6BA,GAG5B,MAAO,CAKNA,IAPDA,EAAMA,GAAO,IAAIC,IAehBC,YAAYC,EAAiBC,GAC5B,IAAMC,EAAWL,EAAIM,IAAIH,GACXE,GAAYA,EAASE,KAAKH,IAEvCJ,EAAIQ,IAAIL,EAAM,CAACC,KAUjBK,aAAaN,EAAiBC,GAC7B,IAAMC,EAAWL,EAAIM,IAAIH,GACrBE,GACHA,EAASK,OAAOL,EAASM,QAAQP,KAAa,EAAG,IAcnDQ,cAAcT,EAAiBU,IAC5Bb,EAAIM,IAAIH,IAAS,IAAyBW,QAAQC,IAAI,SAACX,GAAcA,EAAQS,MAC7Eb,EAAIM,IAAI,MAAQ,IAAiCQ,QAAQC,IAAI,SAACX,GAAcA,EAAQD,EAAMU"}
\ No newline at end of file
diff --git a/vendor/mitt/dist/mitt.js b/vendor/mitt/dist/mitt.js
index fdfe692346d73..2bd0cf9e44e53 100644
--- a/vendor/mitt/dist/mitt.js
+++ b/vendor/mitt/dist/mitt.js
@@ -1,2 +1,2 @@
-module.exports=function(n){return n=n||new Map,{on:function(e,t){var i=n.get(e);i&&i.push(t)||n.set(e,[t])},off:function(e,t){var i=n.get(e);i&&i.splice(i.indexOf(t)>>>0,1)},emit:function(e,t){(n.get(e)||[]).slice().map(function(n){n(t)}),(n.get("*")||[]).slice().map(function(n){n(e,t)})}}};
+module.exports=function(n){return{all:n=n||new Map,on:function(e,t){var i=n.get(e);i&&i.push(t)||n.set(e,[t])},off:function(e,t){var i=n.get(e);i&&i.splice(i.indexOf(t)>>>0,1)},emit:function(e,t){(n.get(e)||[]).slice().map(function(n){n(t)}),(n.get("*")||[]).slice().map(function(n){n(e,t)})}}};
 //# sourceMappingURL=mitt.js.map
diff --git a/vendor/mitt/dist/mitt.js.map b/vendor/mitt/dist/mitt.js.map
index e5d45cedaccc2..37f6f59ebd6bd 100644
--- a/vendor/mitt/dist/mitt.js.map
+++ b/vendor/mitt/dist/mitt.js.map
@@ -1 +1 @@
-{"version":3,"file":"mitt.js","sources":["../src/index.ts"],"sourcesContent":["export type EventType = string | symbol;\n\n// An event handler can take an optional event argument\n// and should not return a value\nexport type Handler = (event?: any) => void;\nexport type WildcardHandler= (type: EventType, event?: any) => void\n\n// An array of all currently registered event handlers for a type\nexport type EventHandlerList = Array<Handler>;\nexport type WildCardEventHandlerList = Array<WildcardHandler>;\n\n// A map of event types and their corresponding event handlers.\nexport type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;\n\nexport interface Emitter {\n\ton(type: EventType, handler: Handler): void;\n\ton(type: '*', handler: WildcardHandler): void;\n\n\toff(type: EventType, handler: Handler): void;\n\toff(type: '*', handler: WildcardHandler): void;\n\n\temit<T = any>(type: EventType, event?: T): void;\n\temit(type: '*', event?: any): void;\n}\n\n/** Mitt: Tiny (~200b) functional event emitter / pubsub.\n *  @name mitt\n *  @returns {Mitt}\n */\nexport default function mitt(all?: EventHandlerMap): Emitter {\n\tall = all || new Map();\n\n\treturn {\n\n\t\t/**\n\t\t * Register an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to listen for, or `\"*\"` for all events\n\t\t * @param {Function} handler Function to call in response to given event\n\t\t * @memberOf mitt\n\t\t */\n\t\ton(type: EventType, handler: Handler) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tconst added = handlers && handlers.push(handler);\n\t\t\tif (!added) {\n\t\t\t\tall.set(type, [handler]);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Remove an event handler for the given type.\n\t\t *\n\t\t * @param {string|symbol} type Type of event to unregister `handler` from, or `\"*\"`\n\t\t * @param {Function} handler Handler function to remove\n\t\t * @memberOf mitt\n\t\t */\n\t\toff(type: EventType, handler: Handler) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tif (handlers) {\n\t\t\t\thandlers.splice(handlers.indexOf(handler) >>> 0, 1);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Invoke all handlers for the given type.\n\t\t * If present, `\"*\"` handlers are invoked after type-matched handlers.\n\t\t *\n\t\t * Note: Manually firing \"*\" handlers is not supported.\n\t\t *\n\t\t * @param {string|symbol} type The event type to invoke\n\t\t * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler\n\t\t * @memberOf mitt\n\t\t */\n\t\temit(type: EventType, evt: any) {\n\t\t\t((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });\n\t\t\t((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });\n\t\t}\n\t};\n}\n"],"names":["all","Map","on","type","handler","handlers","get","push","set","off","splice","indexOf","emit","evt","slice","map"],"mappings":"wBA6B6BA,GAG5B,OAFAA,EAAMA,GAAO,IAAIC,IAEV,CAQNC,YAAGC,EAAiBC,GACnB,IAAMC,EAAWL,EAAIM,IAAIH,GACXE,GAAYA,EAASE,KAAKH,IAEvCJ,EAAIQ,IAAIL,EAAM,CAACC,KAWjBK,aAAIN,EAAiBC,GACpB,IAAMC,EAAWL,EAAIM,IAAIH,GACrBE,GACHA,EAASK,OAAOL,EAASM,QAAQP,KAAa,EAAG,IAcnDQ,cAAKT,EAAiBU,IACnBb,EAAIM,IAAIH,IAAS,IAAyBW,QAAQC,IAAI,SAACX,GAAcA,EAAQS,MAC7Eb,EAAIM,IAAI,MAAQ,IAAiCQ,QAAQC,IAAI,SAACX,GAAcA,EAAQD,EAAMU"}
\ No newline at end of file
+{"version":3,"file":"mitt.js","sources":["../src/index.ts"],"sourcesContent":["export type EventType = string | symbol;\n\n// An event handler can take an optional event argument\n// and should not return a value\nexport type Handler<T = any> = (event?: T) => void;\nexport type WildcardHandler = (type: EventType, event?: any) => void;\n\n// An array of all currently registered event handlers for a type\nexport type EventHandlerList = Array<Handler>;\nexport type WildCardEventHandlerList = Array<WildcardHandler>;\n\n// A map of event types and their corresponding event handlers.\nexport type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;\n\nexport interface Emitter {\n\tall: EventHandlerMap;\n\n\ton<T = any>(type: EventType, handler: Handler<T>): void;\n\ton(type: '*', handler: WildcardHandler): void;\n\n\toff<T = any>(type: EventType, handler: Handler<T>): void;\n\toff(type: '*', handler: WildcardHandler): void;\n\n\temit<T = any>(type: EventType, event?: T): void;\n\temit(type: '*', event?: any): void;\n}\n\n/**\n * Mitt: Tiny (~200b) functional event emitter / pubsub.\n * @name mitt\n * @returns {Mitt}\n */\nexport default function mitt(all?: EventHandlerMap): Emitter {\n\tall = all || new Map();\n\n\treturn {\n\n\t\t/**\n\t\t * A Map of event names to registered handler functions.\n\t\t */\n\t\tall,\n\n\t\t/**\n\t\t * Register an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to listen for, or `\"*\"` for all events\n\t\t * @param {Function} handler Function to call in response to given event\n\t\t * @memberOf mitt\n\t\t */\n\t\ton<T = any>(type: EventType, handler: Handler<T>) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tconst added = handlers && handlers.push(handler);\n\t\t\tif (!added) {\n\t\t\t\tall.set(type, [handler]);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Remove an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to unregister `handler` from, or `\"*\"`\n\t\t * @param {Function} handler Handler function to remove\n\t\t * @memberOf mitt\n\t\t */\n\t\toff<T = any>(type: EventType, handler: Handler<T>) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tif (handlers) {\n\t\t\t\thandlers.splice(handlers.indexOf(handler) >>> 0, 1);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Invoke all handlers for the given type.\n\t\t * If present, `\"*\"` handlers are invoked after type-matched handlers.\n\t\t *\n\t\t * Note: Manually firing \"*\" handlers is not supported.\n\t\t *\n\t\t * @param {string|symbol} type The event type to invoke\n\t\t * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler\n\t\t * @memberOf mitt\n\t\t */\n\t\temit<T = any>(type: EventType, evt: T) {\n\t\t\t((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });\n\t\t\t((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });\n\t\t}\n\t};\n}\n"],"names":["all","Map","on","type","handler","handlers","get","push","set","off","splice","indexOf","emit","evt","slice","map"],"mappings":"wBAgC6BA,GAG5B,MAAO,CAKNA,IAPDA,EAAMA,GAAO,IAAIC,IAehBC,YAAYC,EAAiBC,GAC5B,IAAMC,EAAWL,EAAIM,IAAIH,GACXE,GAAYA,EAASE,KAAKH,IAEvCJ,EAAIQ,IAAIL,EAAM,CAACC,KAUjBK,aAAaN,EAAiBC,GAC7B,IAAMC,EAAWL,EAAIM,IAAIH,GACrBE,GACHA,EAASK,OAAOL,EAASM,QAAQP,KAAa,EAAG,IAcnDQ,cAAcT,EAAiBU,IAC5Bb,EAAIM,IAAIH,IAAS,IAAyBW,QAAQC,IAAI,SAACX,GAAcA,EAAQS,MAC7Eb,EAAIM,IAAI,MAAQ,IAAiCQ,QAAQC,IAAI,SAACX,GAAcA,EAAQD,EAAMU"}
\ No newline at end of file
diff --git a/vendor/mitt/dist/mitt.modern.js b/vendor/mitt/dist/mitt.modern.js
index ccafa5a569689..0777f6de72093 100644
--- a/vendor/mitt/dist/mitt.modern.js
+++ b/vendor/mitt/dist/mitt.modern.js
@@ -1,2 +1,2 @@
-export default function(e){return e=e||new Map,{on(t,n){const s=e.get(t);s&&s.push(n)||e.set(t,[n])},off(t,n){const s=e.get(t);s&&s.splice(s.indexOf(n)>>>0,1)},emit(t,n){(e.get(t)||[]).slice().map(e=>{e(n)}),(e.get("*")||[]).slice().map(e=>{e(t,n)})}}}
+export default function(e){return{all:e=e||new Map,on(t,n){const s=e.get(t);s&&s.push(n)||e.set(t,[n])},off(t,n){const s=e.get(t);s&&s.splice(s.indexOf(n)>>>0,1)},emit(t,n){(e.get(t)||[]).slice().map(e=>{e(n)}),(e.get("*")||[]).slice().map(e=>{e(t,n)})}}}
 //# sourceMappingURL=mitt.modern.js.map
diff --git a/vendor/mitt/dist/mitt.modern.js.map b/vendor/mitt/dist/mitt.modern.js.map
index 650d79e5b50a9..5f669b2d61d0b 100644
--- a/vendor/mitt/dist/mitt.modern.js.map
+++ b/vendor/mitt/dist/mitt.modern.js.map
@@ -1 +1 @@
-{"version":3,"file":"mitt.modern.js","sources":["../src/index.ts"],"sourcesContent":["export type EventType = string | symbol;\n\n// An event handler can take an optional event argument\n// and should not return a value\nexport type Handler = (event?: any) => void;\nexport type WildcardHandler= (type: EventType, event?: any) => void\n\n// An array of all currently registered event handlers for a type\nexport type EventHandlerList = Array<Handler>;\nexport type WildCardEventHandlerList = Array<WildcardHandler>;\n\n// A map of event types and their corresponding event handlers.\nexport type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;\n\nexport interface Emitter {\n\ton(type: EventType, handler: Handler): void;\n\ton(type: '*', handler: WildcardHandler): void;\n\n\toff(type: EventType, handler: Handler): void;\n\toff(type: '*', handler: WildcardHandler): void;\n\n\temit<T = any>(type: EventType, event?: T): void;\n\temit(type: '*', event?: any): void;\n}\n\n/** Mitt: Tiny (~200b) functional event emitter / pubsub.\n *  @name mitt\n *  @returns {Mitt}\n */\nexport default function mitt(all?: EventHandlerMap): Emitter {\n\tall = all || new Map();\n\n\treturn {\n\n\t\t/**\n\t\t * Register an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to listen for, or `\"*\"` for all events\n\t\t * @param {Function} handler Function to call in response to given event\n\t\t * @memberOf mitt\n\t\t */\n\t\ton(type: EventType, handler: Handler) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tconst added = handlers && handlers.push(handler);\n\t\t\tif (!added) {\n\t\t\t\tall.set(type, [handler]);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Remove an event handler for the given type.\n\t\t *\n\t\t * @param {string|symbol} type Type of event to unregister `handler` from, or `\"*\"`\n\t\t * @param {Function} handler Handler function to remove\n\t\t * @memberOf mitt\n\t\t */\n\t\toff(type: EventType, handler: Handler) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tif (handlers) {\n\t\t\t\thandlers.splice(handlers.indexOf(handler) >>> 0, 1);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Invoke all handlers for the given type.\n\t\t * If present, `\"*\"` handlers are invoked after type-matched handlers.\n\t\t *\n\t\t * Note: Manually firing \"*\" handlers is not supported.\n\t\t *\n\t\t * @param {string|symbol} type The event type to invoke\n\t\t * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler\n\t\t * @memberOf mitt\n\t\t */\n\t\temit(type: EventType, evt: any) {\n\t\t\t((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });\n\t\t\t((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });\n\t\t}\n\t};\n}\n"],"names":["all","Map","on","type","handler","handlers","get","push","set","off","splice","indexOf","emit","evt","slice","map"],"mappings":"wBA6B6BA,GAG5B,OAFAA,EAAMA,GAAO,IAAIC,IAEV,CAQNC,GAAGC,EAAiBC,GACnB,MAAMC,EAAWL,EAAIM,IAAIH,GACXE,GAAYA,EAASE,KAAKH,IAEvCJ,EAAIQ,IAAIL,EAAM,CAACC,KAWjBK,IAAIN,EAAiBC,GACpB,MAAMC,EAAWL,EAAIM,IAAIH,GACrBE,GACHA,EAASK,OAAOL,EAASM,QAAQP,KAAa,EAAG,IAcnDQ,KAAKT,EAAiBU,IACnBb,EAAIM,IAAIH,IAAS,IAAyBW,QAAQC,IAAKX,IAAcA,EAAQS,MAC7Eb,EAAIM,IAAI,MAAQ,IAAiCQ,QAAQC,IAAKX,IAAcA,EAAQD,EAAMU"}
\ No newline at end of file
+{"version":3,"file":"mitt.modern.js","sources":["../src/index.ts"],"sourcesContent":["export type EventType = string | symbol;\n\n// An event handler can take an optional event argument\n// and should not return a value\nexport type Handler<T = any> = (event?: T) => void;\nexport type WildcardHandler = (type: EventType, event?: any) => void;\n\n// An array of all currently registered event handlers for a type\nexport type EventHandlerList = Array<Handler>;\nexport type WildCardEventHandlerList = Array<WildcardHandler>;\n\n// A map of event types and their corresponding event handlers.\nexport type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;\n\nexport interface Emitter {\n\tall: EventHandlerMap;\n\n\ton<T = any>(type: EventType, handler: Handler<T>): void;\n\ton(type: '*', handler: WildcardHandler): void;\n\n\toff<T = any>(type: EventType, handler: Handler<T>): void;\n\toff(type: '*', handler: WildcardHandler): void;\n\n\temit<T = any>(type: EventType, event?: T): void;\n\temit(type: '*', event?: any): void;\n}\n\n/**\n * Mitt: Tiny (~200b) functional event emitter / pubsub.\n * @name mitt\n * @returns {Mitt}\n */\nexport default function mitt(all?: EventHandlerMap): Emitter {\n\tall = all || new Map();\n\n\treturn {\n\n\t\t/**\n\t\t * A Map of event names to registered handler functions.\n\t\t */\n\t\tall,\n\n\t\t/**\n\t\t * Register an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to listen for, or `\"*\"` for all events\n\t\t * @param {Function} handler Function to call in response to given event\n\t\t * @memberOf mitt\n\t\t */\n\t\ton<T = any>(type: EventType, handler: Handler<T>) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tconst added = handlers && handlers.push(handler);\n\t\t\tif (!added) {\n\t\t\t\tall.set(type, [handler]);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Remove an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to unregister `handler` from, or `\"*\"`\n\t\t * @param {Function} handler Handler function to remove\n\t\t * @memberOf mitt\n\t\t */\n\t\toff<T = any>(type: EventType, handler: Handler<T>) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tif (handlers) {\n\t\t\t\thandlers.splice(handlers.indexOf(handler) >>> 0, 1);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Invoke all handlers for the given type.\n\t\t * If present, `\"*\"` handlers are invoked after type-matched handlers.\n\t\t *\n\t\t * Note: Manually firing \"*\" handlers is not supported.\n\t\t *\n\t\t * @param {string|symbol} type The event type to invoke\n\t\t * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler\n\t\t * @memberOf mitt\n\t\t */\n\t\temit<T = any>(type: EventType, evt: T) {\n\t\t\t((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });\n\t\t\t((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });\n\t\t}\n\t};\n}\n"],"names":["all","Map","on","type","handler","handlers","get","push","set","off","splice","indexOf","emit","evt","slice","map"],"mappings":"wBAgC6BA,GAG5B,MAAO,CAKNA,IAPDA,EAAMA,GAAO,IAAIC,IAehBC,GAAYC,EAAiBC,GAC5B,MAAMC,EAAWL,EAAIM,IAAIH,GACXE,GAAYA,EAASE,KAAKH,IAEvCJ,EAAIQ,IAAIL,EAAM,CAACC,KAUjBK,IAAaN,EAAiBC,GAC7B,MAAMC,EAAWL,EAAIM,IAAIH,GACrBE,GACHA,EAASK,OAAOL,EAASM,QAAQP,KAAa,EAAG,IAcnDQ,KAAcT,EAAiBU,IAC5Bb,EAAIM,IAAIH,IAAS,IAAyBW,QAAQC,IAAKX,IAAcA,EAAQS,MAC7Eb,EAAIM,IAAI,MAAQ,IAAiCQ,QAAQC,IAAKX,IAAcA,EAAQD,EAAMU"}
\ No newline at end of file
diff --git a/vendor/mitt/dist/mitt.umd.js b/vendor/mitt/dist/mitt.umd.js
index cf39868329fd7..ce0e0059aef8f 100644
--- a/vendor/mitt/dist/mitt.umd.js
+++ b/vendor/mitt/dist/mitt.umd.js
@@ -1,2 +1,2 @@
-!function(e,n){"object"==typeof exports&&"undefined"!=typeof module?module.exports=n():"function"==typeof define&&define.amd?define(n):(e=e||self).mitt=n()}(this,function(){return function(e){return e=e||new Map,{on:function(n,t){var f=e.get(n);f&&f.push(t)||e.set(n,[t])},off:function(n,t){var f=e.get(n);f&&f.splice(f.indexOf(t)>>>0,1)},emit:function(n,t){(e.get(n)||[]).slice().map(function(e){e(t)}),(e.get("*")||[]).slice().map(function(e){e(n,t)})}}}});
+!function(e,n){"object"==typeof exports&&"undefined"!=typeof module?module.exports=n():"function"==typeof define&&define.amd?define(n):(e=e||self).mitt=n()}(this,function(){return function(e){return{all:e=e||new Map,on:function(n,t){var f=e.get(n);f&&f.push(t)||e.set(n,[t])},off:function(n,t){var f=e.get(n);f&&f.splice(f.indexOf(t)>>>0,1)},emit:function(n,t){(e.get(n)||[]).slice().map(function(e){e(t)}),(e.get("*")||[]).slice().map(function(e){e(n,t)})}}}});
 //# sourceMappingURL=mitt.umd.js.map
diff --git a/vendor/mitt/dist/mitt.umd.js.map b/vendor/mitt/dist/mitt.umd.js.map
index b5aaf64a43593..642c89400653d 100644
--- a/vendor/mitt/dist/mitt.umd.js.map
+++ b/vendor/mitt/dist/mitt.umd.js.map
@@ -1 +1 @@
-{"version":3,"file":"mitt.umd.js","sources":["../src/index.ts"],"sourcesContent":["export type EventType = string | symbol;\n\n// An event handler can take an optional event argument\n// and should not return a value\nexport type Handler = (event?: any) => void;\nexport type WildcardHandler= (type: EventType, event?: any) => void\n\n// An array of all currently registered event handlers for a type\nexport type EventHandlerList = Array<Handler>;\nexport type WildCardEventHandlerList = Array<WildcardHandler>;\n\n// A map of event types and their corresponding event handlers.\nexport type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;\n\nexport interface Emitter {\n\ton(type: EventType, handler: Handler): void;\n\ton(type: '*', handler: WildcardHandler): void;\n\n\toff(type: EventType, handler: Handler): void;\n\toff(type: '*', handler: WildcardHandler): void;\n\n\temit<T = any>(type: EventType, event?: T): void;\n\temit(type: '*', event?: any): void;\n}\n\n/** Mitt: Tiny (~200b) functional event emitter / pubsub.\n *  @name mitt\n *  @returns {Mitt}\n */\nexport default function mitt(all?: EventHandlerMap): Emitter {\n\tall = all || new Map();\n\n\treturn {\n\n\t\t/**\n\t\t * Register an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to listen for, or `\"*\"` for all events\n\t\t * @param {Function} handler Function to call in response to given event\n\t\t * @memberOf mitt\n\t\t */\n\t\ton(type: EventType, handler: Handler) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tconst added = handlers && handlers.push(handler);\n\t\t\tif (!added) {\n\t\t\t\tall.set(type, [handler]);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Remove an event handler for the given type.\n\t\t *\n\t\t * @param {string|symbol} type Type of event to unregister `handler` from, or `\"*\"`\n\t\t * @param {Function} handler Handler function to remove\n\t\t * @memberOf mitt\n\t\t */\n\t\toff(type: EventType, handler: Handler) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tif (handlers) {\n\t\t\t\thandlers.splice(handlers.indexOf(handler) >>> 0, 1);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Invoke all handlers for the given type.\n\t\t * If present, `\"*\"` handlers are invoked after type-matched handlers.\n\t\t *\n\t\t * Note: Manually firing \"*\" handlers is not supported.\n\t\t *\n\t\t * @param {string|symbol} type The event type to invoke\n\t\t * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler\n\t\t * @memberOf mitt\n\t\t */\n\t\temit(type: EventType, evt: any) {\n\t\t\t((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });\n\t\t\t((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });\n\t\t}\n\t};\n}\n"],"names":["all","Map","on","type","handler","handlers","get","push","set","off","splice","indexOf","emit","evt","slice","map"],"mappings":"6LA6B6BA,GAG5B,OAFAA,EAAMA,GAAO,IAAIC,IAEV,CAQNC,YAAGC,EAAiBC,GACnB,IAAMC,EAAWL,EAAIM,IAAIH,GACXE,GAAYA,EAASE,KAAKH,IAEvCJ,EAAIQ,IAAIL,EAAM,CAACC,KAWjBK,aAAIN,EAAiBC,GACpB,IAAMC,EAAWL,EAAIM,IAAIH,GACrBE,GACHA,EAASK,OAAOL,EAASM,QAAQP,KAAa,EAAG,IAcnDQ,cAAKT,EAAiBU,IACnBb,EAAIM,IAAIH,IAAS,IAAyBW,QAAQC,IAAI,SAACX,GAAcA,EAAQS,MAC7Eb,EAAIM,IAAI,MAAQ,IAAiCQ,QAAQC,IAAI,SAACX,GAAcA,EAAQD,EAAMU"}
\ No newline at end of file
+{"version":3,"file":"mitt.umd.js","sources":["../src/index.ts"],"sourcesContent":["export type EventType = string | symbol;\n\n// An event handler can take an optional event argument\n// and should not return a value\nexport type Handler<T = any> = (event?: T) => void;\nexport type WildcardHandler = (type: EventType, event?: any) => void;\n\n// An array of all currently registered event handlers for a type\nexport type EventHandlerList = Array<Handler>;\nexport type WildCardEventHandlerList = Array<WildcardHandler>;\n\n// A map of event types and their corresponding event handlers.\nexport type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;\n\nexport interface Emitter {\n\tall: EventHandlerMap;\n\n\ton<T = any>(type: EventType, handler: Handler<T>): void;\n\ton(type: '*', handler: WildcardHandler): void;\n\n\toff<T = any>(type: EventType, handler: Handler<T>): void;\n\toff(type: '*', handler: WildcardHandler): void;\n\n\temit<T = any>(type: EventType, event?: T): void;\n\temit(type: '*', event?: any): void;\n}\n\n/**\n * Mitt: Tiny (~200b) functional event emitter / pubsub.\n * @name mitt\n * @returns {Mitt}\n */\nexport default function mitt(all?: EventHandlerMap): Emitter {\n\tall = all || new Map();\n\n\treturn {\n\n\t\t/**\n\t\t * A Map of event names to registered handler functions.\n\t\t */\n\t\tall,\n\n\t\t/**\n\t\t * Register an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to listen for, or `\"*\"` for all events\n\t\t * @param {Function} handler Function to call in response to given event\n\t\t * @memberOf mitt\n\t\t */\n\t\ton<T = any>(type: EventType, handler: Handler<T>) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tconst added = handlers && handlers.push(handler);\n\t\t\tif (!added) {\n\t\t\t\tall.set(type, [handler]);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Remove an event handler for the given type.\n\t\t * @param {string|symbol} type Type of event to unregister `handler` from, or `\"*\"`\n\t\t * @param {Function} handler Handler function to remove\n\t\t * @memberOf mitt\n\t\t */\n\t\toff<T = any>(type: EventType, handler: Handler<T>) {\n\t\t\tconst handlers = all.get(type);\n\t\t\tif (handlers) {\n\t\t\t\thandlers.splice(handlers.indexOf(handler) >>> 0, 1);\n\t\t\t}\n\t\t},\n\n\t\t/**\n\t\t * Invoke all handlers for the given type.\n\t\t * If present, `\"*\"` handlers are invoked after type-matched handlers.\n\t\t *\n\t\t * Note: Manually firing \"*\" handlers is not supported.\n\t\t *\n\t\t * @param {string|symbol} type The event type to invoke\n\t\t * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler\n\t\t * @memberOf mitt\n\t\t */\n\t\temit<T = any>(type: EventType, evt: T) {\n\t\t\t((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });\n\t\t\t((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });\n\t\t}\n\t};\n}\n"],"names":["all","Map","on","type","handler","handlers","get","push","set","off","splice","indexOf","emit","evt","slice","map"],"mappings":"6LAgC6BA,GAG5B,MAAO,CAKNA,IAPDA,EAAMA,GAAO,IAAIC,IAehBC,YAAYC,EAAiBC,GAC5B,IAAMC,EAAWL,EAAIM,IAAIH,GACXE,GAAYA,EAASE,KAAKH,IAEvCJ,EAAIQ,IAAIL,EAAM,CAACC,KAUjBK,aAAaN,EAAiBC,GAC7B,IAAMC,EAAWL,EAAIM,IAAIH,GACrBE,GACHA,EAASK,OAAOL,EAASM,QAAQP,KAAa,EAAG,IAcnDQ,cAAcT,EAAiBU,IAC5Bb,EAAIM,IAAIH,IAAS,IAAyBW,QAAQC,IAAI,SAACX,GAAcA,EAAQS,MAC7Eb,EAAIM,IAAI,MAAQ,IAAiCQ,QAAQC,IAAI,SAACX,GAAcA,EAAQD,EAAMU"}
\ No newline at end of file
diff --git a/vendor/mitt/dist/index.d.ts b/vendor/mitt/index.d.ts
similarity index 66%
rename from vendor/mitt/dist/index.d.ts
rename to vendor/mitt/index.d.ts
index b37905bcf57f9..55346dd9769a8 100644
--- a/vendor/mitt/dist/index.d.ts
+++ b/vendor/mitt/index.d.ts
@@ -1,19 +1,21 @@
 export declare type EventType = string | symbol;
-export declare type Handler = (event?: any) => void;
+export declare type Handler<T = any> = (event?: T) => void;
 export declare type WildcardHandler = (type: EventType, event?: any) => void;
 export declare type EventHandlerList = Array<Handler>;
 export declare type WildCardEventHandlerList = Array<WildcardHandler>;
 export declare type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;
 export interface Emitter {
-    on(type: EventType, handler: Handler): void;
+    all: EventHandlerMap;
+    on<T = any>(type: EventType, handler: Handler<T>): void;
     on(type: '*', handler: WildcardHandler): void;
-    off(type: EventType, handler: Handler): void;
+    off<T = any>(type: EventType, handler: Handler<T>): void;
     off(type: '*', handler: WildcardHandler): void;
     emit<T = any>(type: EventType, event?: T): void;
     emit(type: '*', event?: any): void;
 }
-/** Mitt: Tiny (~200b) functional event emitter / pubsub.
- *  @name mitt
- *  @returns {Mitt}
+/**
+ * Mitt: Tiny (~200b) functional event emitter / pubsub.
+ * @name mitt
+ * @returns {Mitt}
  */
 export default function mitt(all?: EventHandlerMap): Emitter;
diff --git a/vendor/mitt/package.json b/vendor/mitt/package.json
index 0e1e01b86f541..0105524a0d290 100644
--- a/vendor/mitt/package.json
+++ b/vendor/mitt/package.json
@@ -1,26 +1,27 @@
 {
-  "_from": "mitt@^2.0.1",
-  "_id": "mitt@2.0.1",
+  "_from": "mitt@latest",
+  "_id": "mitt@2.1.0",
   "_inBundle": false,
-  "_integrity": "sha512-FhuJY+tYHLnPcBHQhbUFzscD5512HumCPE4URXZUgPi3IvOJi4Xva5IIgy3xX56GqCmw++MAm5UURG6kDBYTdg==",
+  "_integrity": "sha512-ILj2TpLiysu2wkBbWjAmww7TkZb65aiQO+DkVdUTBpBXq+MHYiETENkKFMtsJZX1Lf4pe4QOrTSjIfUwN5lRdg==",
   "_location": "/mitt",
   "_phantomChildren": {},
   "_requested": {
-    "type": "range",
+    "type": "tag",
     "registry": true,
-    "raw": "mitt@^2.0.1",
+    "raw": "mitt@latest",
     "name": "mitt",
     "escapedName": "mitt",
-    "rawSpec": "^2.0.1",
+    "rawSpec": "latest",
     "saveSpec": null,
-    "fetchSpec": "^2.0.1"
+    "fetchSpec": "latest"
   },
   "_requiredBy": [
+    "#USER",
     "/"
   ],
-  "_resolved": "https://registry.npmjs.org/mitt/-/mitt-2.0.1.tgz",
-  "_shasum": "9e8a075b4daae82dd91aac155a0ece40ca7cb393",
-  "_spec": "mitt@^2.0.1",
+  "_resolved": "https://registry.npmjs.org/mitt/-/mitt-2.1.0.tgz",
+  "_shasum": "f740577c23176c6205b121b2973514eade1b2230",
+  "_spec": "mitt@latest",
   "_where": "/Users/jacktfranklin/src/puppeteer",
   "authors": [
     "Jason Miller <jason@developit.ca>"
@@ -43,13 +44,13 @@
     "eslint": "^7.1.0",
     "eslint-config-developit": "^1.2.0",
     "esm": "^3.2.25",
-    "microbundle": "^0.12.0",
-    "mocha": "^7.2.0",
+    "microbundle": "^0.12.3",
+    "mocha": "^8.0.1",
     "npm-run-all": "^4.1.5",
     "rimraf": "^3.0.2",
     "sinon": "^9.0.2",
     "sinon-chai": "^3.5.0",
-    "ts-node": "^8.10.1",
+    "ts-node": "^8.10.2",
     "typescript": "^3.9.3"
   },
   "eslintConfig": {
@@ -84,12 +85,14 @@
     }
   },
   "eslintIgnore": [
-    "dist"
+    "dist",
+    "index.d.ts"
   ],
   "esmodules": "dist/mitt.modern.js",
   "files": [
     "src",
-    "dist"
+    "dist",
+    "index.d.ts"
   ],
   "homepage": "https://github.com/developit/mitt",
   "jsnext:main": "dist/mitt.es.js",
@@ -101,6 +104,18 @@
   ],
   "license": "MIT",
   "main": "dist/mitt.js",
+  "mocha": {
+    "extension": [
+      "ts"
+    ],
+    "require": [
+      "ts-node/register",
+      "esm"
+    ],
+    "spec": [
+      "test/*_test.ts"
+    ]
+  },
   "module": "dist/mitt.es.js",
   "name": "mitt",
   "repository": {
@@ -113,13 +128,14 @@
     "clean": "rimraf dist",
     "docs": "documentation readme src/index.ts --section API -q --parse-extension ts",
     "lint": "eslint src test --ext ts --ext js",
-    "release": "npm run -s build -s && npm t && git commit -m $npm_package_version && git tag $npm_package_version && git push && git push --tags && npm publish",
-    "test": "npm-run-all --silent typecheck lint testonly",
-    "testonly": "mocha --require esm test/**/*.js",
-    "typecheck": "tsc **/*.ts --noEmit"
+    "mocha": "mocha test",
+    "release": "npm run -s build -s && npm t && git commit -am $npm_package_version && git tag $npm_package_version && git push && git push --tags && npm publish",
+    "test": "npm-run-all --silent typecheck lint mocha test-types",
+    "test-types": "tsc test/test-types-compilation.ts --noEmit",
+    "typecheck": "tsc --noEmit"
   },
   "source": "src/index.ts",
-  "typings": "dist/index.d.ts",
+  "typings": "index.d.ts",
   "umd:main": "dist/mitt.umd.js",
-  "version": "2.0.1"
+  "version": "2.1.0"
 }
diff --git a/vendor/mitt/src/index.ts b/vendor/mitt/src/index.ts
index cfb1cf386cdbd..ae85607f7cfe6 100644
--- a/vendor/mitt/src/index.ts
+++ b/vendor/mitt/src/index.ts
@@ -2,8 +2,8 @@ export type EventType = string | symbol;
 
 // An event handler can take an optional event argument
 // and should not return a value
-export type Handler = (event?: any) => void;
-export type WildcardHandler= (type: EventType, event?: any) => void
+export type Handler<T = any> = (event?: T) => void;
+export type WildcardHandler = (type: EventType, event?: any) => void;
 
 // An array of all currently registered event handlers for a type
 export type EventHandlerList = Array<Handler>;
@@ -13,32 +13,40 @@ export type WildCardEventHandlerList = Array<WildcardHandler>;
 export type EventHandlerMap = Map<EventType, EventHandlerList | WildCardEventHandlerList>;
 
 export interface Emitter {
-	on(type: EventType, handler: Handler): void;
+	all: EventHandlerMap;
+
+	on<T = any>(type: EventType, handler: Handler<T>): void;
 	on(type: '*', handler: WildcardHandler): void;
 
-	off(type: EventType, handler: Handler): void;
+	off<T = any>(type: EventType, handler: Handler<T>): void;
 	off(type: '*', handler: WildcardHandler): void;
 
 	emit<T = any>(type: EventType, event?: T): void;
 	emit(type: '*', event?: any): void;
 }
 
-/** Mitt: Tiny (~200b) functional event emitter / pubsub.
- *  @name mitt
- *  @returns {Mitt}
+/**
+ * Mitt: Tiny (~200b) functional event emitter / pubsub.
+ * @name mitt
+ * @returns {Mitt}
  */
 export default function mitt(all?: EventHandlerMap): Emitter {
 	all = all || new Map();
 
 	return {
 
+		/**
+		 * A Map of event names to registered handler functions.
+		 */
+		all,
+
 		/**
 		 * Register an event handler for the given type.
 		 * @param {string|symbol} type Type of event to listen for, or `"*"` for all events
 		 * @param {Function} handler Function to call in response to given event
 		 * @memberOf mitt
 		 */
-		on(type: EventType, handler: Handler) {
+		on<T = any>(type: EventType, handler: Handler<T>) {
 			const handlers = all.get(type);
 			const added = handlers && handlers.push(handler);
 			if (!added) {
@@ -48,12 +56,11 @@ export default function mitt(all?: EventHandlerMap): Emitter {
 
 		/**
 		 * Remove an event handler for the given type.
-		 *
 		 * @param {string|symbol} type Type of event to unregister `handler` from, or `"*"`
 		 * @param {Function} handler Handler function to remove
 		 * @memberOf mitt
 		 */
-		off(type: EventType, handler: Handler) {
+		off<T = any>(type: EventType, handler: Handler<T>) {
 			const handlers = all.get(type);
 			if (handlers) {
 				handlers.splice(handlers.indexOf(handler) >>> 0, 1);
@@ -70,7 +77,7 @@ export default function mitt(all?: EventHandlerMap): Emitter {
 		 * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler
 		 * @memberOf mitt
 		 */
-		emit(type: EventType, evt: any) {
+		emit<T = any>(type: EventType, evt: T) {
 			((all.get(type) || []) as EventHandlerList).slice().map((handler) => { handler(evt); });
 			((all.get('*') || []) as WildCardEventHandlerList).slice().map((handler) => { handler(type, evt); });
 		}